A typical electronic package may include, for example, a printed circuit board ("PCB") having various electronic parts disposed thereon. Specifically, these electronic parts may include active parts such as integrated circuit ("IC") chips, passive parts such as resistors and capacitors, and other parts such as connectors, mechanical fasteners, fans and switches. Thus, a broad array of electronic parts compose a typical electronic package.
The design of an electronic package including a PCB includes, for example, the design of the circuit interconnections and the layout of the parts on the PCB. Various considerations must be given to the parts layout such as, for example, the length and sizing of wiring between parts. Further placement considerations include thermal management of the PCB, typically cooling. Specifically, for example, the PCB is desirably laid out such that a coolant (e.g., a fluid or a gas) may flow around the parts on the PCB providing cooling thereof. Furthermore, it is desirable to space high-powered parts from each other such that excess heat is not developed in one localized section of the PCB.
The traditional approach to designing a PCB layout based upon thermal considerations involves manually estimating the proper layout of the board to minimize heat buildup and then manufacturing a corresponding prototype. The prototype is tested to confirm that thermal problems do not exist. 0f course, if there are thermal problems, another prototype has to be designed and built, and the process is repeated. This could continue for many iterations, thus requiring the commensurate time and expense involved in designing and building multiple hardware prototypes. Furthermore, in many cases, the resulting design is still not optimal. Thus, the traditional approach to PCB layout based on thermal considerations is problematic.
In recent years, there has been a significant increase in the use of advanced techniques for solving electronic cooling problems. As one example, computational fluid dynamics ("CFD") has been used to analyze the thermal behavior of electronic packages and the electronic parts contained therein. More specifically, recent CFD techniques use finite control volume analysis wherein, for example, each electronic part is subdivided into multiple finite control volumes upon which CFD analysis is performed. This requires the assignment of boundary conditions and material properties to each of the finite control volumes.
As an example, an electronic part is broken up into multiple right parallelepiped shaped finite control volumes in a process called discretization. Each finite control volume is then assigned material properties and boundary conditions such that CFD analysis can be performed. The material properties may include, for example, power density and thermal conductivity. Boundary conditions are imposed for each surface of the finite control volume; in this example, for each of the six faces of each of the right parallelepiped shaped finite control volumes. Appropriate volumetric boundary conditions are also assigned as needed.
Specifically, boundary conditions may include, for example, solid-to-solid, fluid-to-fluid or solid-to-fluid boundary conditions. To explain, if a finite control volume is disposed completely internal to a solid part, each of its six boundary conditions will be solid-to-solid. Similarly, if a finite control volume is disposed completely within a fluid, then each of its boundary conditions will be fluid-to-fluid. However, if a finite control volume has one of its six surfaces coplanar with the outside surface of a solid part which is surrounded by a fluid, then that boundary condition is solid-to-fluid because it demarcs the interface between the solid part and the surrounding fluidic environment (coolant). Designation of these boundary conditions facilitates analysis by a finite control volume based CFD tool.
Up to this date, the assignment of material properties and boundary conditions to finite control volumes has been a tedious and difficult task. By way of example, the conventional process used for creating a finite control volume model of a part is summarized below.
Initially, a wireframe model is created representing only the geometry of the current part. The wireframe model is then subdivided into finite control volumes, each being absent in material property and boundary condition definitions. Thereafter, each finite control volume is manually assigned material properties and boundary conditions such that CFD analysis may be performed. It is important to note that more detailed analysis requires smaller, and therefore more, finite control volumes. Thus, as the detail of analysis required increases, there are more finite control volumes to have boundary conditions and material properties assigned thereto such that the task of assigning such information becomes prohibitive. Moreover, the problem is further compounded as the number of parts increase as with system level modelling.
The present invention is directed towards solving the above-noted problems.